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Scientists have long been looking for liquid water on Mars. Now, an Italian team has fallen on an entire lake. The sensational discovery raises the question: could there be life there?
The 20-kilometer lake is 1.5 kilometers under the ice of the Marssüdpol, reports a team around the Italian astrophysicist Roberto Orosei in the journal "Science". Although liquid water is a prerequisite for life as we know it. Signs of underground life, however, can not be inferred from radar observations with the Mars Express spacecraft.
Roberto Orosei explains the discovery; (c) Stefano Parisini, INAF Media
The observation concludes a decade-long debate about the existence of liquid water on the Red Planet, points out the American Society for the Protection of the Red Sea. Advancement of Science (AAAS), editor of "Science".
Once Similar to the Earth
Rivers and dried sediments show that there must have been liquid water on the red planet billions of years ago. At that time, the climate was warmer and the Martian atmosphere was more dense than today. Even an entire ocean could have covered large parts of the young Mars.
For decades, researchers have been searching for liquid water on the planet next to Earth. Today, however, water exists on Mars, especially in the form of ice in the polar ice caps. There is a low level of water vapor in Mars' thin air.
In recent years, scientists have discovered various traces of liquid water on Mars. For example, water droplets have struck NASA's "Phoenix" module and, on some of the steep slopes of the red planet, seasonal currents have been observed that could have come from the melting of ice. ;water. There are also indications that liquid water could form a thin layer beneath the Martian surface regularly, but briefly, in small amounts.
Discovery at the South Pole
Liquid water on the surface of Mars can not exist permanently today. For over 30 years, however, researchers have suggested that under the ice caps, there could be bags of liquid water – similar to the subterranean lakes of Antarctica and Greenland on Earth. The "Mars Express" radio data now confirm this hypothesis.
ESA, INAF, Davis, Borga, INAF media
Radar signals show a huge underwater lake
With the probe of European Space Agency (ESA) researchers have Orosei excavated parts of the Southern Planum Austral South Pole region on Mars. There, they arrived on a well-defined area with the same radar signatures as they create lakes hidden under the ice of terrestrial polar regions.
It is unclear whether there may be life in the underground glacial lake on Mars. When other explorers buried the subterranean Whillans Lake in Antarctica, they encountered many microbes in the "eternal darkness". However, Whillans Lake is not a closed ecosystem, its waters are slowly but regularly exchanged through an underground river. In addition, it is still much colder at Marssüdpol than at Antarctica. Researchers estimate the temperature of the underground lake now uncovered at minus 68 degrees C.
The lake is salty
To remain liquid in this icy cold, the underground lake must be full of salts that can significantly lower the freezing point . Magnesium, calcium and sodium salts are widespread on Mars. It is therefore quite plausible that they also occur in the underground lake, say the researchers around Orosei. The necessary salinity does not make people's lives easier, but we know that microorganisms even survive high salt levels.
The underground oceans on the different ice orbits of the Jupiter and Saturn planets are currently considered the most promising places for extraterrestrial research. Life in our solar system. It remains to be seen whether the underground glacier of Mars joins this rank.
After all, it may not be an isolated case: only a fraction of the southern polar cap was examined by radar and its spatial resolution was limited. There is no reason to badume that liquid groundwater occurs only at this point on Mars, the authors point out.
science.ORF.at/dpa
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